Gravity-escapement for clocks.



E. A. HUMMBL. GRAVITY ESCAPEMENT FOR CLOCKS.

APPLICATION IILED 11116.25, 1911.

1,097,637. Patented May 26, 1914.

2 SHEETS-SHEET 1.

PH co., WASHINGTON, D. c.

E. A. HUMMEL.

GRAVITY ESGAPEMENT FOR CLOCKS.

APPLIOATIDN FILED AUG. 25, 1911.

Patented May 26, 1914.

2 SHEETS-SHEET 2.

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V UNITED STATES PATENT ()FFICE;

ERNEST A. HUMMEL, OF ST. PAUL, MINNESOTA, ASSIGNOR T0 ALBERT L. HAMAN, OF ST. PAUL, MINNESOTA.

GRAVITY-ESGAPEMENT roa oLocKs.

Patented May 26, 1914.

To all whom it may concern:

a citizen of the United States, residing at St. Paul, in the county of Ramsey and State of Minnesota, have invented certain new and useful Improvements in Gravity-Escapements for Clocks, of which the following is a specification.

My invention relates to improvements in gravity escapements for clocks, its object being to provide a gravity escapement which shall be simple and eflicient, and which can be used in short pendulum clocks to make the seconds hand beat once instead of twice with every double swing of the pendulum.

'It is desirable for time comparison and other reasons that the seconds hand should beat seconds, but in many clocks a seconds pendulum, that is a pendulum which makes one oscillation or single swing in a second, would be inconveniently long, so that resort has been had to a short pendulum which makes one oscillation every half second. This, with the escapements now in use, causes the seconds hand to beat half seconds. The escapement which is the subject of this invention, however, when used with such a pendulum, will cause the seconds hand to beat seconds instead of half seconds. One embodiment of the invention is shown in the accompanying drawings, in which- Figure 1 is a front view of the escapement mechanism, partly broken away, showing the escape wheel held at rest and the gravity pallet swung almost out of the orbit of the lifting pins; Fig. 2 is a similar View, but showing the escape wheel released from the stop pallets and the gravity arm receiving its return impulse from the escape wheel; Fig. 3 is a side view of the escapement mechanism; Fig. 4 is a detail showing the position of the gravity pallet when lifted by the final impact of'the pendulum; and Fig. 5 is a perspective view of the stop pallets.

In the drawings A represents the frame of the clock, B the pendulum, and C the escape wheel, which is here shown as a star wheel with six long teeth or leaves. The escape wheel is fast upon the arbor 2, and is driven from the seconds hand arbor 3 by means of the meshing gears 4 upon the seconds hand arbor and 5 upon the escape wheel arbor 2. Also fast upon the arbor 2 and rotatable with the escape wheel are siX lifting pins 6, here shown integral with the escape wheel and in the form of peripheral teeth upon the hub thereof.

Fast upon the arbor 7 above the escape wheel and suspended therefrom is a one legged gravity arm D, having at its lower end a pin 8 in position to engage the pendulum. The gravity arm is outwardly bowed, and at its middle point has an inwardly proecting lug 9 carrying a pallet 10 in position to be engaged successively by the lifting pins 6 of the escape wheel. I have herein called this pallet the gravity pallet to dis tinguish it from the stop pallets hereinafter mentioned.

Fast upon the arbor 7, and preferably integral with the gravity arm D as shown in the drawings is a crank arm 11 having an inturned finger 12 which forms an outer stop pallet for the teeth or leaves of the escape wheel. The arm 11 oscillates up and down as the gravity arm swings back and forth, thereby alternately stopping and releasing the successive teeth of the escape wheel. Pivotally supported upon the frame at 13 on the other side of the arbor 7 is a long arm 14, terminating in an inturned finger 15 In operation, when the pendulum has reached the limit of its return or outward swing to the right, the parts will stand in the position shown in full lines in Fig. 1, with one of the teeth of the escape wheel held by the outer stop pallet 12, and the gravity arm held out by a lifting pin with its pallet 10 almost out of the orbit of travel of the pin. The pendulum in its return swing to nearly the right has just reached the lower end of the gravity arm and its impact upon the pin 8 will move the gravity arm just enough farther to lift the outer stop pallet and release the intercepted tooth of the escape wheel, and at the same time to lift the pallet 10 out of the orbit of the lifting pin, as shown in Fig. i. This movement of the pendulum and gravity arm is very slight, as will be seen from the dotted lines in Fig. 1 indicating the final position of the pendulum. The escape wheel is thus free to move, but its released tooth will be immediately intercepted again by the inner stop pallet 15. In the meantime the gravity arm, whose pallet 10 is now clear of the lifting pin, will swing inwardly, driving the pendulum before it, and at the same time raising the crank arm 18 until the pin 17, acting upon the arm 14, lifts the inner stop pallet 15 sufficiently to release the intercepted tooth of the escape wheel. The release will occur just before the gravity pallet 10 reaches and lodges against the next lifting pin, as shown in dotted lines in Fig. 1. In this forward movement of the gravity arm the outer stop pallet 12 will be turned down again into the path When thus released, the escape wheel will turn in the direction of f the arrow, as shown in Fig. 2, until the neXt succeeding escape tooth is stopped by the outer pallet 12, and its lifting pin, acting upon the gravity pallet 10, will lift the gravity arm and swing it back to the locked '1 position shown in full lines in Fig. 1, while of the escape wheel.

the pendulum will continue its oscillation to the left independently of the gravity arm.i The crank arm 18, which works with the gravity arm, will at the same time be turned down away from the arm 14 so as to permlt the inner stop pallet carried thereby to drop down again into the orbit of the escape teeth. The pendulum Wlll 1n the meantime have completed its oscillation to the left and overtaken the gravity arm 111 its return swing to the right. upon the gravity arm, which is now held out by the lifting pin, will move the gravity arm just enough farther to release the escape The impact of the pendulum tooth from the stop pallet 12 and the gravity pallet 10 from the lifting pin, as described above, and another forward swing of the gravity arm and pendulum will take place.

By holding the gravity arm out, as shown in Fig. 1, until the pendulum overtakes it, the

pendulum will lee enabled to complete its full return swing without interference from the gravity arm, and the impulse of the gravity arm will always be first communicated to the pendulum at the beginning of its forward swing, the impact of the pendulum being utilized to release the gravity arm from the lift- 5 ing pin. Thus the escape wheel Wlll be per-' mitt-ed to make only one effective turning movement at each double swing of the penduhim, for the release movement from the stop 12 to the stop 15 is so small as to be practically negligible in its effect upon the seconds hand. The seconds hand will thus be made to beat but once with each double swing of the pendulum, so that if the pendulum is a half second pendulum the seconds hand will beat seconds instead of half seconds.

The term lifting is used in the claims to indicate broadly the moving of the stop pallets out of the path of the escape wheel, whether such movement be up, down, to one side or otherwise.

I claim as myinvention:

1. In an escapement for clocks, the combination with the pendulum and escape wheel, of a one legged gravity arm, a pair of juxtaposed stop pallets for the escape Wheel, whereby successively to intercept the same tooth of the escape wheel, pendulum actuated means for lifting one of said'pallets and means independent of the pendulum for lifting the other of said pallets.

2. In an escapement for clocks, the combination with the pendulum and escape wheel, of a one legged gravity arm and a pair of juxtaposed stop pallets operated thereby, whereby successively to intercept the same tooth of the escape wheel, one of said pallets being lifted as the gravity arm swings in one direction and the other pallet being lifted as the gravity arm swings in the opposite direction.

In an escapement for clocks, the combination with the pendulum and escape Wheel, of a one legged gravity arm impelled by the escape wheel in one direction only and moving in the other direction by gravity only, and a pair of stop pallets operated thereby, one of said pallets being lifted as the gravity arm swings in one direction and the other pallet being lifted as the gravity arm swings in the opposite direction.

4. In an escapement for clocks, the combination with the pendulum and escape wheel, of a pair of stop pallets arranged in the path of the wheel whereby successively to intercept the same tooth of the escape wheel, pendulum actuated means for lifting one of said pallets and gravity actuated means for lifting the other of said pallets.

5. In'an escapement for clocks, the combination with the pendulum, and the escape wheel, of a gravity arm, a pair of juxtaposed stop pallets one of which is carried by the gravity arm and actuated thereby under the pendulum-impelled swing of said arm, the other being independently mounted, and means for actuating the independently mounted pallet by the gravity-actuated fall of the gravity arm.

6. In an escapement for clocks, the combination with the pendulum, and escape wheel,

gravity arm for actuation thereby under the gravity-induced movement of said arm.

In testimony whereof I aflix my signature in presence of two Witnesses.

ERNEST A. HUMMEL.

Witnesses:

ARTHUR P. Lo'rrmor, H. SWANSON.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

Washington, D. G. 

